JP2008201031A - Image forming apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of an image quality due to disagreement of a state of an image forming apparatus with a gamma curve used in gamma conversion processing. <P>SOLUTION: Image data transmitted from a printing controller 2 is subjected to gamma conversion processing on the basis of the gamma curve. The image data subjected to gamma conversion processing is stored in an image memory 13. In the image forming apparatus 1 which carries out image formation on the basis of the image data stored in the image memory 13, in the case of carrying out image formation of a plurality of copies, if it is selected to execute correction of the gamma curve even during the execution of a job, the image data is transmitted also after the second copy from the printing controller 2. If it is selected not to execute correction of the gamma curve during the execution of the job, only the image data of the first copy is transmitted from the printing controller 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a program for outputting image data received via a print controller.

  Generally, in an image forming apparatus having a printer output function, gamma conversion processing is performed in order to match image data received from a print controller with output gradation characteristics of each apparatus. Since the state of the image forming apparatus changes from time to time, it is necessary to correct the gamma curve used for gamma conversion processing according to the state of the image forming apparatus in order to maintain a constant gradation and stabilize the image quality. There is.

For example, a composite copying apparatus that corrects a gamma correction table for a printer when a printer job is received for the first time after power-on has been proposed (see, for example, Patent Document 1). Unlike the apparatus that always corrects the gamma correction table when the power is turned on, this composite copying apparatus prevents correction even when it is not actually used as a printer.
JP 2004-181670 A

  By the way, an image forming apparatus that performs gamma conversion processing when receiving image data from the print controller, stores the image data subjected to the gamma conversion processing in an image memory, and forms an image based on the image data stored in the image memory. However, there is a case where a mismatch occurs between the current state of the apparatus and the image data already subjected to the gamma conversion processing in the image memory, and there is a problem that the image quality is deteriorated.

  For example, when forming a plurality of image sets, the image data is transferred for each unit in the job, and only the first set of image data is transferred. It is conceivable that image formation is performed based on data. In the former case, an image forming apparatus that does not perform gamma curve correction during job execution is suitable for the current apparatus state and the past apparatus state. There is a possibility that a mismatch occurs between the image data subjected to the gamma conversion processing by the gamma curve. On the other hand, in the latter case, even if the gamma curve is corrected during the output of the second and subsequent copies, image formation is performed based on the image data already stored in the image memory. It was not reflected.

  The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to prevent deterioration in image quality due to a mismatch between the state of the image forming apparatus and the gamma curve used for gamma conversion processing.

  In order to solve the above problem, the invention described in claim 1 performs gamma conversion processing on the image data transferred from the print controller based on the gamma curve, and stores the image data subjected to the gamma conversion processing in the image memory. In the image forming apparatus that forms an image based on the image data stored in the image memory, the correction unit that executes the correction of the gamma curve and the correction of the gamma curve even while the job is being executed. A selection unit for selecting whether or not to perform, and when performing image formation of a plurality of copies, when the selection unit selects to execute the correction of the gamma curve even during execution of a job, The image data is transferred from the print controller to the second and subsequent copies, and the gamma curve is corrected while the job is being executed by the selection means. When it does not line is selected, characterized in that and a transfer control means for transferring only the image data of the first copy from the print controller.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, when performing image formation of a plurality of copies, it is selected that the gamma curve correction is not performed during job execution by the selection unit. In the second and subsequent copies, image formation is performed based on the first copy image data transferred from the print controller.

  According to a third aspect of the present invention, image data transferred from the print controller is subjected to gamma conversion processing based on a gamma curve, the image data subjected to the gamma conversion processing is stored in an image memory, and the image data is stored in the image memory. A computer that causes the image forming means to form an image based on the obtained image data, a correction function that performs the correction of the gamma curve, and whether or not to execute the correction of the gamma curve even during execution of a job. When a selection function for selection and image formation of a plurality of copies are performed, if the execution of the gamma curve is selected even when a job is being executed in the selection function, the print controller 2 The image data is transferred after the second copy, and the gamma curve correction is not executed during the job execution in the selection function. Preparative When is selected, a program for implementing the, the transfer control function of transferring only the image data of the first copy from the print controller.

  According to a fourth aspect of the present invention, in the program according to the third aspect, when the computer forms a plurality of sets of images, the selection function does not execute the correction of the gamma curve during job execution. Is selected, the image forming unit is allowed to realize an image formation control function for performing image formation on the second and subsequent copies based on the first copy image data transferred from the print controller. Features.

  According to the present invention, when the gamma curve correction is selected even while the job is being executed, the second and subsequent copies of the image data are transferred from the print controller. It is possible to prevent a decrease in image quality due to a mismatch with a gamma curve used for gamma conversion processing. On the other hand, when the gamma curve correction is selected not to be executed during execution of the job, only the first copy of the image data is transferred from the print controller, so that the efficiency of image data transfer can be improved.

First, an embodiment of the present invention will be described in detail.
FIG. 1 shows a system configuration of an image forming system 100 according to an embodiment of the present invention.
As shown in FIG. 1, an image forming system 100 includes an image forming apparatus 1, a print controller 2, and a PC (Personal Computer) 3. The image forming apparatus 1 and the print controller 2, and the print controller 2 and the PC 3 are Each is connected so that data can be transmitted and received. Based on the user's operation, the print instruction and the image data to be subjected to the print instruction are transmitted from the PC 3, transferred to the image forming apparatus 1 by the print controller 2, and image formation based on the image data is performed by the image forming apparatus 1. Is called.

FIG. 2 shows the configuration of the image forming apparatus 1.
As shown in FIG. 2, the image forming apparatus 1 includes a gamma conversion processing unit 11, a compression circuit 12, an image memory 13, an expansion circuit 14, an LD (Laser Diode) drive circuit 15, an LD 16, a drum 17, a transfer belt 18, and an optical. A type sensor 19, a CPU (Central Processing Unit) 20, a display / operation unit 21, a mechanical drive unit 22, a work memory 23, and the like are provided.

  The gamma conversion processing unit 11 performs gamma conversion processing on the image data transferred from the print controller 2 based on the gamma correction table 11a. The gamma correction table 11a stores data indicating a gamma curve (tone correction curve) used for gamma conversion processing. That is, in the present embodiment, the gamma conversion process based on the gamma curve means a gamma conversion process based on the gamma correction table 11a, and the gamma curve correction (hereinafter referred to as gamma curve correction) means the gamma correction table. It means 11a correction.

  The compression circuit 12 performs compression processing on the image data after the gamma conversion processing.

  The image memory 13 is composed of DRAM (Dynamic RAM) and HDD (Hard Disk Drive), and stores image data after gamma conversion processing and compression processing.

  The decompression circuit 14 performs decompression processing on the image data stored in the image memory 13.

  The LD drive circuit 15 drives the LD 16 based on the image data subjected to the expansion process by the expansion circuit 14.

  The LD 16 emits a laser beam based on the image data, and forms an electrostatic latent image on the charged drum 17. Then, toner adheres to the electrostatic latent image formed on the drum 17 to form a toner image. The toner image formed on the drum 17 is transferred to the transfer belt 18 and further transferred to a recording medium such as paper. The toner image is fixed on the recording medium by being heated and pressurized by a fixing device (not shown).

  The optical sensor 19 is provided so as to face the transfer belt 18, and detects the toner adhesion amount of the test pattern formed on the transfer belt 18 and outputs it to the CPU 20 when performing gamma curve correction. As the test pattern, a staircase pattern in which the density is changed little by little is used.

  The CPU 20 reads various processing programs stored in a ROM (Read Only Memory) (not shown), and comprehensively controls the processing operation of each unit of the image forming apparatus 1 in cooperation with the program.

  The CPU 20 controls a communication interface (not shown) and transmits / receives data to / from the print controller 2. The CPU 20 receives a print instruction and image data transmitted from the print controller 2.

  The CPU 20 determines whether a condition for executing gamma curve correction (hereinafter referred to as an execution condition for gamma curve correction) is satisfied based on a predetermined condition. As determination conditions, for example, conditions such as every predetermined time, every predetermined number of sheets, and when the power is turned on are set in advance.

  When the CPU 20 performs image formation of a plurality of copies based on information selected by the user's operation from the display / operation unit 21 and indicating whether or not to execute gamma curve correction even during job execution. Set the transfer mode. A job is a unit indicating a series of operations related to image formation in the image forming apparatus 1. For example, when outputting a plurality of sheets, a series of operations relating to the output of the plurality of sheets is one job, and when outputting a plurality of copies, a series of operations relating to the output for a plurality of copies is one job. Specifically, when the gamma curve correction is selected even during the execution of the job, the CPU 20 performs the first transfer for transferring the image data from the print controller 2 for the second and subsequent copies. When the mode is set and it is selected not to execute the gamma curve correction during the execution of the job, the print controller 2 sets the second transfer mode in which only the first set of image data is transferred.

  When the first transfer mode is set, the CPU 20 executes the gamma curve correction when the execution condition for the gamma curve correction is satisfied even when the job is being executed. Specifically, the CPU 20 controls the LD driving circuit 15 based on the image data for the test pattern to drive the LD 16 to form a test pattern on the drum 17 and transfer it from the drum 17 onto the transfer belt 18. . Then, the CPU 20 rewrites the gamma correction table 11a based on the toner adhesion amount detected by the optical sensor 19 from the test pattern on the transfer belt 18 so that the gradation characteristics are appropriate.

  When the second transfer mode is set, the CPU 20 does not execute gamma curve correction during execution of a job even if a gamma curve correction execution condition is satisfied. In addition, when a plurality of sets of images are formed in the state where the second transfer mode is set, the CPU 20 also transfers the first set of image data transferred from the print controller 2 for the second and subsequent copies. Based on the above, image formation is performed. If the second transfer mode is set, it may not be determined whether the execution condition for the gamma curve correction is satisfied during execution of the job.

  The display / operation unit 21 includes an LCD (Liquid Crystal Display), a touch panel provided so as to cover the LCD, and various function buttons, and displays various operation screens and various processing results in accordance with instructions from the CPU 20. Further, the display / operation unit 21 outputs an operation signal operated by a touch panel or various function buttons to the CPU 20. The display / operation unit 21 is selection means for selecting whether or not to execute gamma curve correction even during execution of a job.

  The mechanical drive unit 22 drives each unit of the image forming apparatus 1 in accordance with instructions from the CPU 20.

  The work memory 23 is a memory that temporarily stores a program read from the ROM, various data, parameters, and the like in various processes executed by the CPU 20.

  The print controller 2 includes a control unit, an image memory, and the like, receives a print instruction and image data transmitted from the PC 3, and transfers them to the image forming apparatus 1.

  The PC 3 transmits a print instruction and image data to the print controller 2 based on a user operation instruction.

Next, the operation will be described.
FIG. 3 is a flowchart showing image transfer mode setting processing executed in the image forming apparatus 1. Note that a program for realizing the processing described in the flowchart of FIG. 3 is stored in a ROM (not shown), and the CPU 20 reads the program from the ROM and sequentially executes operations according to the program. Further, in the image forming apparatus 1, whether or not to perform gamma curve correction is selected according to an operation instruction from the display / operation unit 21 of the user even during execution of a job.

  When the gamma curve correction operation during execution of the job is valid (step A1; YES), the image forming apparatus 1 is set to the first transfer mode (step A2). Then, the print controller 2 is requested to transfer image data in the first transfer mode (step A3).

  On the other hand, if the gamma curve correction operation during execution of the job is not valid (step A1; NO), the image forming apparatus 1 is set to the second transfer mode (step A4). Then, the print controller 2 is requested to transfer image data in the second transfer mode (step A5).

  Next, transfer processing in the first transfer mode will be described. FIG. 4 is a ladder chart showing transfer processing in the first transfer mode.

  First, when a print instruction of a plurality of copies (N copies: N is an integer) is transmitted from the print controller 2 to the image forming apparatus 1 (step B1), a request for the first copy of image data is sent from the image forming apparatus 1 to the print controller 2. Is transmitted (step B2), and the image data of the first copy is transferred from the print controller 2 to the image forming apparatus 1 accordingly (step B3). In the image forming apparatus 1, the first image forming operation is performed based on the received first image data (step B4). Specifically, the gamma conversion processing unit 11 performs gamma conversion processing on the received first image data based on the gamma correction table 11a. Then, compression processing is performed on the image data after the gamma conversion processing by the compression circuit 12 and stored in the image memory 13. The image data stored in the image memory 13 is subjected to expansion processing by the expansion circuit 14, and the LD driving circuit 15 drives the LD 16 based on the image data subjected to the expansion processing, thereby forming an image.

  Next, a second copy image data request is transmitted from the image forming apparatus 1 to the print controller 2 (step B5), and the second copy image data is transferred from the print controller 2 to the image forming apparatus 1 accordingly (step B5). Step B6). In the image forming apparatus 1, an image forming operation for the second copy is performed based on the received image data for the second copy (step B7).

  In the first transfer mode, the gamma curve correction is executed even while the job is being executed. Therefore, when the execution condition of the gamma curve correction is satisfied while the image forming operation of a plurality of copies is being performed, The CPU 20 executes gamma curve correction (step B8), and the gamma correction table 11a is rewritten (step B9). Specifically, the CPU 20 controls the LD drive circuit 15 to drive the LD 16 based on the test pattern image data, thereby forming a test pattern on the drum 17 and transferring the drum 17 onto the transfer belt 18. Is done. Then, based on the toner adhesion amount detected from the test pattern on the transfer belt 18 by the optical sensor 19, the CPU 20 rewrites the gamma correction table 11a so that the gradation characteristics are appropriate.

  After the gamma curve correction, the remaining image forming operation continues. An image data request for the Nth copy is transmitted from the image forming apparatus 1 to the print controller 2 (step B10), and the image data for the Nth copy is transferred from the print controller 2 to the image forming apparatus 1 accordingly (step B11). . In the image forming apparatus 1, the Nth image forming operation is performed based on the received Nth image data (step B12).

  Next, transfer processing in the second transfer mode will be described. FIG. 5 is a ladder chart showing transfer processing in the second transfer mode.

  First, when a print instruction for a plurality of copies is transmitted from the print controller 2 to the image forming apparatus 1 (step C1), a request for the first image data is transmitted from the image forming apparatus 1 to the print controller 2 (step C2). Accordingly, the first set of image data is transferred from the print controller 2 to the image forming apparatus 1 (step C3). In the image forming apparatus 1, the first image forming operation is performed based on the received first image data (step C4). Specifically, the gamma conversion processing unit 11 performs gamma conversion processing on the received first image data based on the gamma correction table 11a. Then, compression processing is performed on the image data after the gamma conversion processing by the compression circuit 12 and stored in the image memory 13. The image data stored in the image memory 13 is subjected to expansion processing by the expansion circuit 14, and the LD driving circuit 15 drives the LD 16 based on the image data subjected to the expansion processing, thereby forming an image.

  Next, an image forming operation for the second copy is performed based on the image data for the first copy stored in the image memory 13 (step C5). In this way, the image forming operation is performed up to the Nth copy (step C6).

  In the second transfer mode, the gamma curve correction is not executed during the execution of the job, and the second and subsequent copies are also formed based on the first set of image data transferred from the print controller 2.

  As described above, according to the image forming apparatus 1, when execution of gamma curve correction is selected even during execution of a job, image data is transferred from the print controller 2 to the second and subsequent copies. Therefore, it is possible to prevent a decrease in image quality due to a mismatch between the state of the image forming apparatus 1 and the gamma curve used for the gamma conversion process. On the other hand, when it is selected not to perform gamma curve correction during the execution of a job, only the first copy of image data is transferred from the print controller 2, so that the efficiency of image data transfer can be improved.

  The description in the above embodiment is an example of the image forming apparatus according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of each part constituting the apparatus can be changed as appropriate without departing from the spirit of the present invention.

1 is a system configuration diagram of an image forming system 100 according to an embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus 1. FIG. 4 is a flowchart showing image transfer mode setting processing executed in the image forming apparatus 1. It is a ladder chart which shows the transfer process in 1st transfer mode. It is a ladder chart which shows the transfer process in 2nd transfer mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming system 1 Image forming apparatus 11 Gamma conversion process part 11a Gamma correction table 12 Compression circuit 13 Image memory 14 Expansion circuit 15 LD drive circuit 16 LD
17 Drum 18 Transfer Belt 19 Optical Sensor 20 CPU
21 Display / Operation Unit 22 Mechanical Drive Unit 23 Work Memory 2 Print Controller 3 PC

Claims (4)

Gamma conversion processing is performed on the image data transferred from the print controller based on the gamma curve, the image data subjected to the gamma conversion processing is stored in the image memory, and image formation is performed based on the image data stored in the image memory. In the image forming apparatus to perform,
Correction means for executing correction of the gamma curve;
A selection means for selecting whether or not to execute the correction of the gamma curve even during execution of a job;
When performing image formation of a plurality of copies, image data is transferred from the print controller to the second and subsequent copies if the gamma curve correction is selected even when the job is being executed by the selection means. Transfer control means for transferring only the first set of image data from the print controller when the selection means selects not to execute correction of the gamma curve during execution of the job;
An image forming apparatus comprising:   When performing image formation of a plurality of copies, if it is selected that the gamma curve correction is not performed during execution of the job by the selection unit, the second copy and subsequent copies are also transferred from the print controller. The image forming apparatus according to claim 1, wherein image formation is performed based on image data of the second set. Image data transferred from the print controller is subjected to gamma conversion processing based on a gamma curve, the image data subjected to the gamma conversion processing is stored in an image memory, and image forming means is based on the image data stored in the image memory On a computer that lets you
A correction function for correcting the gamma curve;
A selection function for selecting whether or not to execute the correction of the gamma curve even during execution of a job;
When performing image formation of a plurality of copies, image data is transferred from the print controller to the second and subsequent copies if correction of the gamma curve is selected even when a job is being executed in the selection function. A transfer control function for transferring only the first set of image data from the print controller when it is selected that the correction of the gamma curve is not executed during execution of the job in the selection function;
A program to realize In the computer,
When performing image formation of a plurality of copies, if it is selected that the gamma curve correction is not performed during execution of the job in the selection function, the image forming means also prints the print for the second and subsequent copies. 4. The program according to claim 3, wherein an image formation control function for forming an image based on the first set of image data transferred from the controller is realized.

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